machine-learning-ex4

function checkNNGradients（lambda）
%CHECKNNGRADIENTS Creates a small neural network to check the
%backpropagation gradients
%   CHECKNNGRADIENTS（lambda） Creates a small neural network to check the
%   backpropagation gradients it will output the analytical gradients
%   produced by your backprop code and the numerical gradients （computed
%   using computeNumericalGradient）. These two gradient computations should
%   result in very similar values.
%

if ~exist（‘lambda‘ ‘var‘） || isempty（lambda）
    lambda = 0;
end

input_layer_size = 3;
hidden_layer_size = 5;
num_labels = 3;
m = 5;

% We generate some ‘random‘ test data
Theta1 = debugInitializeWeights（hidden_layer_size input_layer_size）;
Theta2 = debugInitializeWeights（num_labels hidden_layer_size）;
% Reusing debugInitializeWeights to generate X
X  = debugInitializeWeights（m input_layer_size - 1）;
y  = 1 + mod（1:m num_labels）‘;

% Unroll parameters
nn_params = [Theta1（:） ; Theta2（:）];

% Short hand for cost function
costFunc = @（p） nnCostFunction（p input_layer_size hidden_layer_size ...
                               num_labels X y lambda）;

[cost grad] = costFunc（nn_params）;
numgrad = computeNumericalGradient（costFunc nn_params）;

% Visually examine the two gradient computations.  The two columns
% you get should be very similar. 
disp（[numgrad grad]）;
fprintf（[‘The above two columns you get should be very similar.
‘ ...
         ‘（Left-Your Numerical Gradient Right-Analytical Gradient）

‘]）;

% Evaluate the norm of the difference between two solutions.  
% If you have a correct implementation and assuming you used EPSILON = 0.0001 
% in computeNumericalGradient.m then diff below should be less than 1e-9
diff = norm（numgrad-grad）/norm（numgrad+grad）;

fprintf（[‘If your backpropagation implementation is correct then 
‘ ...
         ‘the relative difference will be small （less than 1e-9）. 
‘ ...
         ‘
Relative Difference: %g
‘] diff）;

end

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----

    .......      1950  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4checkNNGradients.m

    .......      1095  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4computeNumericalGradient.m

    .......       841  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4debugInitializeWeights.m

    .......      1502  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4displayData.m

    .......      8099  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4ex4.m

    .......   7511764  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4ex4data1.mat

    .......     79592  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4ex4weights.mat

    .......      8749  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4fmincg.m

    .......      1624  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libjsonlabAUTHORS.txt

    .......      3862  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libjsonlabChangeLog.txt

    .......       881  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libjsonlabjsonopt.m

    .......      1551  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libjsonlabLICENSE_BSD.txt

    .......     18732  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libjsonlabloadjson.m

    .......     15574  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libjsonlabloadubjson.m

    .......       771  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libjsonlabmergestruct.m

    .......     19369  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libjsonlabREADME.txt

    .......     17462  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libjsonlabsavejson.m

    .......     16123  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libjsonlabsaveubjson.m

    .......      1094  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libjsonlabvarargin2struct.m

    .......      1195  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libmakeValidFieldName.m

    .......      5562  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libsubmitWithConfiguration.m

    .......      3210  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4
nCostFunction.m

    .......       585  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4predict.m

    .......       903  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4
andInitializeWeights.m

    .......       137  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4sigmoid.m

    .......       677  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4sigmoidGradient.m

    .......      1635  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4submit.m

    .......    356692  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4.pdf

     目录          0  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4libjsonlab

     目录          0  2017-03-14 09:40  machine-learning-ex4machine-learning-ex4ex4lib

............此处省略6个文件信息